Although black women produce less vitamin D in their skin with sun exposure, researchers found that black and white women absorb and metabolize the vitamin at the same rate.

The study will be published in the Journal of Clinical Endocrinology & Metabolism.

"African-American women don't have to worry about taking larger doses of vitamin D to compensate," said study lead author Dr. J. Chris Gallagher, of Creighton University School of Medicine in Omaha, in a journal news release. "They should follow the current medical guidelines for vitamin D supplementation suggested recently by the Institute of Medicine."

In conducting the double-blind study, the researchers gave older black and white women of similar body types various doses of vitamin D. Although women with darker skin tend to have lower levels of 25-hydroxyvitamin D or 25OHD, an indicator used to measure vitamin D levels, black and white women had similar responses to their supplements.

The researchers concluded that black women struggling with a vitamin D deficiency should received the same dose as white women to treat their condition.

The body's primary source of vitamin D is sunlight -- not food, the release noted. People who are deficient in vitamin D can develop abnormalities in calcium, phosphorus and bone metabolism. Children suffering from a lack of vitamin D could develop rickets or a bone-softening condition called osteomalacia. Adults with a vitamin D deficiency may experience muscle weakness.